One method of repairing damaged sewer pipe is to excavate the area surrounding the sewer pipe and replace the broken portion. This is a very expensive and labor intensive solution, and is also an inconvenience to residents living in the area and utilizing roadways overlying the area.
Another solution is to reline the sewer pipes on site. Such methods typically utilize a resin coated liner which is inserted into the existing sewer pipe line and fitted against the interior of the sewer pipe. The liner is held against the interior of the pipe while the resin cures to form a new pipe lining within the existing pipe.
One example of such a method is shown in U.S. Pat. No. 4,366,012. In this patent, a process utilizing an elongated bladder tube having an inner tubular liner comprised of felt is shown. Uncured resin is introduced into the bladder tube and is used to impregnate the felt inner liner. The bladder tube and the tubular liner are then inserted into the end of the sewer pipe to be repaired, and moved to the area of the sewer pipe needing repair. Upon reaching the area of the sewer pipe needing repair, the impregnated felt liner is inverted out of the bladder tube so that it is on the outside surface of the bladder tube and is pressed against the interior surface of the sewer pipe. When the resin cures, a new pipe liner is provided at the area to be repaired.
In many cases connection of lateral pipes to main sewer lines for residential or other customers was frequently accomplished by forming a hole in the main line with a sledge or the like. The lateral pipe was then simply abutted against the hole, and then the excavation back filled to cover the juncture. Often, this juncture of the lateral with the main line would leak, and would not provide a tight sealed connection.
With the growing concern regarding the environmental impact of sewage leakage, such junctures are primary concern for repair, and can be repaired simultaneously with the lining of the lateral pipe by the method of the present invention.